Add commitlint configuration and compliance checks #1

	# SPDX-FileCopyrightText: 2026 Institute for Automation of Complex Power Systems, RWTH Aachen University
	# SPDX-License-Identifier: Apache-2.0

	name: Compliance checks

	on:
	pull_request:
	branches: [master, main]

	permissions:
	contents: read

	jobs:
	conventional-commits:
	name: Conventional commit messages
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v7
	with:
	fetch-depth: 0

	- uses: actions/setup-node@v5
	with:
	node-version: "20"

	- name: Install commitlint
	run: npm install --no-save @commitlint/cli @commitlint/config-conventional

	# The merge commit takes the PR title, so that is what Release Please reads.
	- name: Fail if the pull request title is not a conventional commit
	env:
	PR_TITLE: ${{ github.event.pull_request.title }}
	run: \|
	if ! printf '%s\n' "$PR_TITLE" \| npx commitlint --verbose; then
	echo ""
	echo "The pull request title becomes the merge commit subject on master."
	echo "Use a conventional commit subject, for example:"
	echo ""
	echo " fix: Coding style"
	echo ""
	exit 1
	fi

	- name: Fail if a commit in this branch is not a conventional commit
	run: \|
	BASE=${{ github.event.pull_request.base.sha }}
	HEAD=${{ github.event.pull_request.head.sha }}
	if ! npx commitlint --from "$BASE" --to "$HEAD" --verbose; then
	echo ""
	echo "Rewrite the offending commit messages, then force-push:"
	echo ""
	echo " git rebase -i $BASE"
	echo " git push --force-with-lease"
	echo ""
	echo "Or install the pre-commit hooks (see CONTRIBUTING.md) to catch this locally."
	exit 1
	fi

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